The production of conventional textile substrates for PCB and like applications is known to be a complex, multi-step process. The production of such substrates from staple fibers begins with the carding process where the fibers are opened and aligned into a feedstock known as sliver. Several strands of sliver are then drawn multiple times on a drawing frames to further align the fibers, blend, improve uniformity as well as reduce the sliver's diameter. The drawn sliver is then fed into a roving frame to produce roving by further reducing its diameter as well as imparting a slight false twist. The roving is then fed into the spinning frame where it is spun into yarn. The yarns are next placed onto a winder where they are transferred into larger packages. The yarn is then ready to be used to create a fabric.
For a woven fabric, the yarns are designated for specific use as warp or fill yarns. The fill yarns (which run on the y-axis and are known as picks) are taken straight to the loom for weaving. The warp yarns (which run on the x-axis and are known as ends) must be further processed. The large packages of yarns are placed onto a warper frame and are wound onto a section beam were they are aligned parallel to each other. The section beam is then fed into a slasher where a size is applied to the yarns to make them stiffer and more abrasion resistant, which is required to withstand the weaving process. The yarns are wound onto a loom beam as they exit the slasher, which is then mounted onto the back of the loom. The warp yarns are threaded through the needles of the loom, which raises and lowers the individual yarns as the filling yarns are interested perpendicular in an interlacing pattern thus weaving the yarns into a fabric. Once the fabric has been woven, it is necessary for it to go through a scouring process to remove the size from the warp yarns before it can be dyed or finished. Currently, commercial high-speed looms operate at a speed of 1000 to 1500 picks per minute, where a pick is the insertion of the filling yarn across the entire width of the fabric. Sheeting and bedding fabrics are typically counts of 80×80 to 200×200, being the ends per inch and picks per inch, respectively. The speed of weaving is determined by how quickly the filling yarns are interlaced into the warp yams; therefore looms creating bedding fabrics are generally capable of production speeds of 5 inches to 18.75 inches per minute.
In contrast, the production of nonwoven fabrics from staple fibers and/or filaments is known to be more efficient than traditional textile processes as the fabrics are produced directly from the carding process.
Nonwoven fabrics are suitable for use in a wide variety of applications where the efficiency with which the fabrics can be manufactured provides a significant economic advantage for these fabrics versus traditional textiles. Hydroentangled fabrics have been developed with improved properties, which are a result of the entanglement of the fibers, and/or filaments in the fabric providing improved fabric integrity. Subsequent to entanglement, fabric durability can be further enhanced by the application of binder compositions and/or by thermal stabilization of the entangled fibrous matrix.
Previously, the manufacture of electronic components, such as a printed circuit board, utilized woven fiberglass of either continuous yarns or rovings. Weaving fiberglass is known to be highly detrimental to weaving components, as well as difficult to handle due to hazards imposed by the fine glass filaments. By the utilization of hydroentangled, three-dimensionally imaged support substrates, PCB's, and similar applications, can not only be fabricated from a variety of fibrous components of significantly reduced hazardous nature, but are also imparted with unique and useful performance properties, which improve the overall structural, electrical, and thermal performance of the circuit board. A particular advantage of the improvement in thermal control of the substrate formed in accordance with the present invention, highly temperature sensitive electrical component, such as advanced computer processors, can attain further benefit from the substrate being better able to dissipate heat. With reduced temperature, such things as processor speed and battery life can be increased further.